Examples of frictional force in the following topics:
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- Recall that the force of friction depends on both the coefficient of friction and the normal force.
- As always, the frictional force resists motion.
- If the maximum frictional force is greater than the force of gravity, the sum of the forces is still 0.
- The force of friction can never exceed the other forces acting on it.
- The frictional forces only act to counter motion.
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- Another type of frictional force is static friction, otherwise known as stiction.
- Like kinetic friction, the force of static friction is given by a coefficient multiplied by the normal force.
- In general, the force of static friction can be represented as:
- As with all frictional forces, the force of friction can never exceed the force applied.
- Any force larger than that overcomes the force of static friction and causes sliding to occur.
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- The force of friction is what slows an object sliding over a surface.
- The force of friction can be represented by an equation: $F_{\text{friction}} = \mu F_n$.
- $F_n$ is called the normal force and is the force of the surface pushing up on the object.
- Frictional forces always oppose motion or attempted motion between objects in contact.
- Much of the friction is actually due to attractive forces between molecules making up the two objects, so that even perfectly smooth surfaces are not friction-free.
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- External forces: forces caused by external agent outside of the system.
- There are mainly three kinds of forces: Gravity, normal force (between ice & pucks), and frictional forces during the collision between the pucks
- With this in mind, we can see that gravity and normal forces are external, while the frictional forces between pucks are internal.
- Without knowing anything about the internal forces (frictional forces during contact), we learned that the total momentum of the system is a conserved quantity (p1 and p2 are momentum vectors of the pucks. ) In fact, this relation holds true both in elastic or inelastic collisions.
- (neglecting frictional loss in the system. )
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- Net force affects the motion, postion and/or shape of objects (some important and commonly used forces are friction, drag and deformation).
- Specifically, we will discuss the forces of friction, air or liquid drag, and deformation.
- Friction is a force that resists movement between two surfaces sliding against each other.
- Friction is not itself a fundamental force, but arises from fundamental electromagnetic forces between the charged particles constituting the two contacting surfaces.
- Like friction, the force of drag is a force that resists motion.
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- Conservation of mechanical energy states that the mechanical energy of an isolated system remains constant without friction.
- Conservation of mechanical energy states that the mechanical energy of an isolated system remains constant in time, as long as the system is free of all frictional forces.
- In any real situation, frictional forces and other non-conservative forces are always present, but in many cases their effects on the system are so small that the principle of conservation of mechanical energy can be used as a fair approximation.
- Now, if the conservative force, such as the gravitational force or a spring force, does work, the system loses potential energy (PE).
- Remember that the law applies to the extent that all the forces are conservative, so that friction is negligible.
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- Ff: the friction force of the ramp.
- There is a potential difficulty also with the arrow representing friction.
- Now, the tip of the friction arrow is at the highest point of the base.
- The engineer in this instance has assumed a rigid body scenario and that the friction force is a sliding vector and thus the point of application is not relevant.
- These forces can be friction, gravity, normal force, drag, tension, etc...
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- The drag force is the resistive force felt by objects moving through fluids and is proportional to the square of the object's speed.
- Another interesting force in everyday life is the force of drag on an object when it is moving in a fluid (either a gas or a liquid).
- You feel the drag force when you move your hand through water.
- Like friction, the drag force always opposes the motion of an object.
- Unlike simple friction, the drag force is proportional to some function of the velocity of the object in that fluid.
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- In the presence of dissipative forces, total mechanical energy changes by exactly the amount of work done by nonconservative forces (Wc).
- Here we will adopt the strategy for problems with dissipative forces.
- Using energy considerations, calculate the distance the 65.0-kg baseball player slides, given that his initial speed is 6.00 m/s and the force of friction against him is a constant 450 N.
- Strategy: Friction stops the player by converting his kinetic energy into other forms, including thermal energy.
- The work done by friction is negative, because f is in the opposite direction of the motion (that is, θ=180º, and so cosθ=−1).
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- In an "ideally banked curve," the angle $\theta$ is chosen such that one can negotiate the curve at a certain speed without the aid of friction.
- In an "ideally banked curve," the angle $\theta$ is such that you can negotiate the curve at a certain speed without the aid of friction between the tires and the road.
- For ideal banking, the net external force equals the horizontal centripetal force in the absence of friction.
- The only two external forces acting on the car are its weight $w$ and the normal force of the road $N$.
- Friction helps, because it allows you to take the curve at greater or lower speed than if the curve is frictionless.